Poire is the traditional name in France. Elsewhere, butchers sell the same piece — or a close cousin — under a different name.
Both *morceaux du boucher* — small premium muscles on the round, traditionally kept by French butchers. Araignée is the spider-shaped muscle on the rear thigh; poire is the pear-shaped muscle on the inside thigh. Different muscles, same cultural-identity category.
Companion *morceau du boucher* — both small premium muscles on the round, both historically reserved by French butchers, both quick-cook tender cuts.